Well scraping apparatus



June 14, 1955 a. M. sclvALLY WELL scRAPING APPARATUS 2 Sheets-Sheet l Filed Sept. 18, l951 /R y mm 1m .l/ CV om e 4rc c ATTORNEY June 14, 1955 B. M. sclvALLY WELL sCRAPING APPARATUS 2 Sheets-Sheet 2 Filed Sept. 18 1951 Bern/ce M JC/VU//y Y INVENTOR.

WELL SCRAPING APPARATUS Bernice M. Scivally, Houston, Tex.

Application September 18, 1951, Serial No. 247,037

4 Claims. (Cl. 166-173) This invention relates to well scraping apparatus, and more particularly to a casing scraper adapted to be inserted in a well casingfor scraping the inside of the same.

The present application is a continuation in part of a previous application of the same applicant for a casing scraper, Serial Number 145,001, tiled February 18, 1950, now Patent No. 2,627,925, issued February l0, 1953.

The invention has for an important object the provision of well scraping apparatus which is adapted for attachment to a string of drill pipe, whereby the same may be lowered into a well casing for smoothing and conditioning the inside of the same.

Another object of the invention is to provide well scraping apparatus which is constructed to be inserted in a string of drill pipe to follow the cutting bit, for the purpose of scraping off cement, or the like, left inside the casing from a previous cementing operation, and for removing burs resulting from the perforation of the casing.

A further object of the invention is the provision of well scraping apparatus which is eliective for removing material coating the inside of a well casing either by upward or downward movement of the apparatus in the casing, or by rotation of the same therein.

Another object of the invention is to provide well scraping apparatus, which includes a body adapted for insertion in a string of drill pipe, and which is provided with scraping blades movable radially outwardly of the body for engagement with the material to be removed, said apparatus including means for yieldably maintaining the scraping blades in extended condition by a predetermined force.

The invention, briey stated, comprises a tubular body adapted for insertion in a drill pipe, or the like, and having means for the attachment thereto of a cutting bit, said body being provided with slots therethrough, with scraping blades movably positioned in the slots and yieldable means inside the body responsive to a predetermined pressure therein to yieldably maintain the scraping blades in extended condition.

The above and other objects and advantages of the invention will be apparent from the following description, constituting a specification of the same, when taken in conjunction with the annexed drawings, wherein- Figures 1, 1A and 1B are fragmentary side elevational views, partly in cross section, showing the upper, middle, and lower portions of a well scraping tool embodying the invention;

Figure 2 is a cross sectional view, taken along the line 2-2 of Figure 1, looking in the direction indicated by the arrows; and

Figure 3 is a cross sectional view taken along the line 3 3 of Figure 1B, looking in the direction indicated by the arrows.

The invention as illustrated `in Figures 1, 1A and 1B is shown in position for operation in a Well casing, which is indicated at 10. Such a casing may have been previrice ously perforated, resulting in the formation of burs or other irregularities in the interior surface thereof, or the well may have been subjected to cementing or other process and thereafter -rebored, leaving a coating of cement or the like, which it is desired to remove by a scraping operation. It is for the purpose of removing such burs or coating, or other irregularities on the intrior surface of the casing that the present scraping apparatus has been designed.

Referring now to the drawings in greater detail, wherein like numerals of reference are used to designate the same parts throughout the several views, the scraping tool has a body of generally cylindrical shape made up of an upper connector member 12, intermediate vtubular members 14 and 16, and a lower connector member or sub 18. The upper connector member 12 is provided at its upper end with an internally threaded portion 20 by which this member may be connected to a drill pipe, and mediate its ends is provided with an externally threaded portion 22 of reduced diameter, for the attachment thereto of the upper end of the intermediate tubular section 14, which is provided with corresponding internal threads. Below the portion 22, the upper connector member is formed with a lower end portion 24 of further reduced diameter, for a purpose hereinafter explained.

The intermediate tubular section 14 has an inwardly thickened portion 26, forming an internal annular shoulder 28 mediate the ends of this section, and at its lower end is provided with an externally threaded portion 30 of reduced diameter, for the attachment thereto of the upper end of the intermediate tubular section 16 which is provided with corresponding internal threads. The lower end of the intermediate section 16 is likewise provided with internal threads, and the lower connector member or sub 1.8-has an externally threaded upper end portion 32, of reduced diameter, upon which the lower end of the section 16 is threaded.

The lower end of the sub 18 is internally threaded, as indicated at 34, for the attachment thereto ofa drill stem, or the like.

Within the body of the tool and extending into the intermediate section 14, through the intermediate section 16, and into the sub 18, there is a longitudinally movable inner tubular member 36, which carries at its upper end an annular piston 38 attached thereto by suitable threads, as indicated at 40. The piston 38 has an external annular groove 42, in which is disposed suitable packing, such as an O-ring d4, which forms a fluid tight seal between the piston and the intermediate section 14 and an internal annular groove 48 may also be provided on the piston 33, for the retention of suitable packing, such as the O- ring 50, to form a fluid tight seal between the piston and the inner tubular member 36.

The upper end portion 32 of the sub 18 is preferably provided with external and internal grooves 52 and 54, respectively, in which suitable packing, such as the O-rings 56 and S8, respectively, are disposed, the ring 56 forming a iluid tight seal between the sub 18 and the intermediate section 16, while the ring 58 forms a fluid tight seal between the sub and the inner tubular member 36. v

The internally thickened portion 26 at the lower end of the intermediate section 14 is provided with longitudinal, peripherially spaced, internal grooves 60,'so that a coritinuous luid filled chamber is formed between the inner tubular member 36 and the intermediate sections 14. and 16, which chamber extends from the lower surface ofthe piston 38 to the upper end surface of the sub 18. Thus uid in the space indicated at 62, between the lower'surface of the piston 38 and the shoulder 2S of the intermediate section 14, may ow through the grooves 60 into the space indicated at 64, between the inner tubular mem"- ber 36 and the intermediate section 16, upon downward movement of the piston, and also return through these grooves upon upward movement of the piston.

Intermediate section 16 is provided with a series of `openings 66, arranged in spaced relation thereabout, the

openings being preferably in the form of elongated slots, and being in circumferential overlapping relation. Scraping blades 68 of somewhat smaller cross-sectional area than the openings 66 project through the openings and extend radially outwardly of the body, each of these blades being provided with a backing plate 70 disposed within the body. The backing plates 70 may, if desired, be of such a size and shape as to form when assembled a compl-ete helix in the form of a substantially continuous cylinder lining the interior of the intermediate section .1.6, between the lower end of the intermediate section 14 and the upper end of the sub 18.

Within the space 64 of the uid chamber, and in engagement with the backing plates 70, a yieldable element 72 is positioned, which element may take the form of a flexible cylinder of rubber or the like, adapted to operate under the influence of the pressure of the lluid in the chamber to maintain the scraping blades in their extended condition. The tubular element 72 is preferably formed at its ends with internal annular lips 74, which seat against the lower end surface of the intermediate section 14, and against the upper end surface of the sub 18, to form uid tight seals to prevent the escape of pressure uid from the chamber.

Above the piston 3S, within the intermediate section 14 there is a resilient member, preferably in the form of a coil spring 76, which surrounds the reduced end portion 24 of the upper connector member 12, and bears at its lower end against the piston 38 and at its upper end against the reduced portion 22 of the connector member. This resilient member exerts a predetermined downward force against the piston 38 tending to move the piston downwardly against the fluid in the fluid filled chamber, so that a constant pressure is exerted against the yieldable element 72, to yieldingly maintain the scraping blades 63 in their extended condition.

An opening 78 is provided through the intermediate section 14 leading into the space 62 of the fluid chamber, which opening is closed by suitable means, such as a screw plug 80, for the purpose of supplying fluid to the fluid chamber when desired.

The outer ends of the blades 63 are preferably somewhat rounded, and the upper and lower edges of the blades may be of hardened metal or provided with a beat treated metal coating 82 of hastelite or the like.

In making use of the invention the parts are assembled in the manner shown in Figures l, 1A and 1B, the upper connector member 12 being left off, and the fluid chamber is filled through the opening 7S, which is then closed by the plug 80. Thereafter the upper connector member may be attached, whereby the resilient member 76 is placed under compressure, thus applying a predetermined force to the piston 38, and pressure to the yieldable cylindrical member 72, to yieldably maintain the cutting blades in their extended condition. The tool is then attached to the lower end of the drill pipe and the cutting bit attached to the lower end of the tool. The device in this condition may be lowered and pushed down into the casing so that the scraping blades engage and scrape otf material on the inside of the casing. Rotation of the drill then results in an upward spiral or helical scraping action of the blades.

It will be noted that the helical arrangement of the scraping blades produced an upward movement of any material scraped by the blades from the inside of the casing. Moreover, due to the spacing of the blades, the drilling mud or fluid may pass freely between the same and any material, such as cement, steel, burs, or other cuttings produced by the cutting bit may be borne upwardly therewith.

It will also be apparent that the scraping blades extend entirely about the periphery of the tool, so that they will perform a cutting action when the drill pipe is raised or lowered as well as when it is rotated.

Due to the arrangement of the resilient element 76 exerting a downward pressure on the piston 38, which is transmitted to the fluid in the fluid chamber, the scraping blades are yieldably maintained in their extended condition, and in the event that the blades encounter some obstruction in the casing, they may move inwardly against the pressure of the yieldable member 72, so that breakage or injury to the blades does not result. Inward movement of the scraping blades applies additional pressure to the fluid in the fluid chamber, and this additional pressure is transmitted through the piston 38 to the resilient member 76, thus avoiding any danger of leakage or damage to the tool which might result from such increase of pressure. This arrangement makes possible the use of an hydraulic fluid, such as oil in the fluid chamber, whereby a constant predetermined force may be exerted to maintain the scraping blades in extended condition. It will also be apparent that drilling fluid or the like may pass through the apparatus, without affecting the operation of the same in any manner, and that the outward force on the scraping blades is entirely independent of any pressure conditioned in the well.

The construction and arrangement of the various parts is, of course, subject to numerous modifications, and it will be understood that the embodiment shown and described herein is intended by way of illustration, and is not to be regarded as limiting the invention, which is defined in the appended claims.

What is claimed as new and desired to secure by Letters Patent is:

l. In well scraping apparatus a tubular body adapted to be positioned in the bore of a well, a tubular member in the body spaced inwardly thereof, an annular fluid filled chamber formed between the member and the body, means on the member in sliding engagement with the body and forming one end of the chamber, means on the body in sliding engagement with the member and forming the other end of the chamber, said member being movable longitudinally of the body to vary the length of the chamber, yieldable means in the body positioned to coact with the body and member to yieldably urge the member in a direction to decrease the length of the chamber, said body having a plurality of spaced openings opening into said chamber and leading to the exterior of the body, scraper means carried by the body and extending through and movably positioned in the openings for movement radially of the body, a tubular expansible element of resilient material in the chamber whose interior is exposed to the pressure of fluid in the chamber and whose exterior is in sealing engagement at its opposite ends with the interior of the body to cause the element to be expanded by the pressure of fluid in the chamber, said element being positioned for engagement with the scraper means to yieldingly urge the scraper means outwardly of the body.

2. In well scraping apparatus a tubular body adapted to be positioned in the bore of a well, a tubular member in the body spaced inwardly thereof, an annular fluid filled chamber formed between the member and the body, means on the member in sliding engagement with the body and forming one end of the chamber, means on the body in sliding engagement with the member and forming the other end of the chamber, said member being movable longitudinally of the body to vary the length of the chamber, yieldable means in the body positioned to coact with the body and member to yieldingly urge the member in a direction to decrease the length of the chamber, said body having a plurality of spaced openings opening into said chamber and leading to the exterior of the body, scraper means carried by the body and extending through and movably positioned in the openings for movement radially of the body, a tubular expansible element in the chamber whose opposite ends are in sealing engagement with the interior of the body and whose exterior is in engagement with the scraper means, the interior of said element being exposed to the pressure of fluid in said chamber to cause the element to yieldingly urge the scraper means outwardly of the body.

3. In well scraping apparatus a tubular body adapted to be positioned in the bore of a well, a tubular member in the body spaced inwardly thereof, an annular iluid filled chamber formed between the member and the body, means on the member in sliding engagement with the body and forming one end of the chamber, means on the body in sliding engagement with the member and forming the other end of the chamber, said member being movable longitudinally of the body to vary the length of the chamber, yieldable means in the body positioned to coact with the body and member to yieldingly urge the member in a direction to decrease the length of the chamber, said body having a plurality of spaced openings opening into said chamber and leading to the exterior of the body, scraper means carried by the body extending through and movably positioned in the openings for movement radially of the body, a backing plate on each of the scraper means inside the chamber, a tubular expansible element in the chamber whose interior is exposed to the pressure of iluid in the chamber and whose exterior is in engagement with said backing plates and in sealing engagement at its opposite ends with the interior of the body to cause said element to be expanded by the pressure of uid in the chamber to yieldingly urge the scraper means outwardly of the body.

4. In well scraping apparatus a tubular body, adapted to be positioned in the bore of a well, a tubular member in the body spaced inwardly thereof, an annular fluid filled chamber formed between the member and body,

means on the member in sliding engagement with the body and forming one end of the chamber, means on the body in sliding engagement with the member and forming the other end of the chamber, said member being movable longitudinally of the body to vary the length of the chamber, yieldable means in the body positioned to coact with the body and member to yieldingly urge the member in a direction to decrease the length of the chamber, said body having a plurality of spaced openings helically disposed about its periphery opening into the chamber and leading to the exterior of the body, scraper means carried by the body extending through and movably positioned in the openings for movement radially of the body and whose outer extremities are formed with edge portions which are orf-set around the circumference of the body so that they cover the entire horizontal projection of the circumference of the body, a curved backing plate on each of the scraper means inside the chamber, said backing plates forming a substantially continuous cylindrical surface, a tubular expansible element in the chamber whose opposite ends are in sealing engagement with the interior of the body and whose exterior is in engagement with said cylindrical surface, the interior of said element being exposed to the pressure of fluid in said chamber to cause the element to yieldingly urge said scraper means outwardly of the body.

References Cited in the file of this patent `UNTTED STATES PATENTS 2,151,416 Black et a1. Mar. 21, 1939 2,427,052 Grant Sept. 9, 1947 2,438,673 McMahan Mar. 30, 1948 2,447,966 Stephens Aug. 24, 1948 2,567,475 Hall Sept. 11, 1951 2,627,925 Scivally Feb. 10, 1953 

